Selection device, selection method, and program

Abstract

The present invention pertains to a selection device for selecting, from a plurality of scenarios to be simulated in a wireless communication system, a specific scenario to be applied to control, the selection device comprising: a calculation unit that calculates a probability distribution of an evaluation index by executing a simulation for each of the plurality of scenarios; and a selection unit that selects the specific scenario from among the plurality of scenarios on the basis of the probability distribution.

Description

Selection device, selection method, and program

[0001] The present invention relates to a technique for controlling a wireless communication system based on a simulation.

[0002] In recent years, various wireless communication standards have been developed, and wireless technologies that can keep up with ever-changing user demands and radio wave conditions to provide a natural communication environment that does not require users to be aware of the wireless network are also being studied (e.g., Non-Patent Document 1).

[0003] In wireless technologies in general, including the wireless technologies described above, a technique for predicting the communication quality of a wireless communication system by simulation is an important technique.

[0004] Motoharu Sasaki, Toshiro Nakahira, Takatsune Moriyama, Tomoaki Ogawa, Yusuke Asai, and Yasushi Takatori, "Multi-radio Proactive Control Technology (Cradio(r)): A Natural Communication Environment where Users Do Not Need to Be Aware of the Wireless Network" NTT Technical Review, Vol. 19, No. 8, Aug. 2021. https: / / www.ntt-review.jp / archive / ntttechnical.php?contents=ntr202108ra1.pdf&mode=show_pdf

[0005] By performing a simulation for a wireless communication system, it is possible to select a specific scenario from among a plurality of scenarios, and to perform station placement design and control of the actual wireless communication system based on the specific scenario.

[0006] In conventional techniques such as Non-Patent Document 1, control and the like are performed based on predictions obtained from simulations of wireless communication systems. Because the predictions are used as the basis, random errors are included, but no method is provided for reflecting the random errors in control.

[0007] Furthermore, when selecting a specific scenario from multiple scenarios based on conventional techniques that do not take into account random errors, etc., there is a possibility that an inappropriate scenario will be selected.

[0008] The present invention has been made in consideration of the above points, and aims to provide a technique that enables an appropriate scenario to be selected from a plurality of scenarios based on a simulation of a wireless communication system.

[0009] According to the disclosed technology, there is provided a selection device for selecting a specific scenario to be applied to control from a plurality of scenarios to be simulated in a wireless communication system, the selection device comprising: a calculation unit that calculates a probability distribution of an evaluation index by executing a simulation for each of the plurality of scenarios; and a selection unit that selects the specific scenario from the plurality of scenarios based on the probability distribution.

[0010] The disclosed technology provides a technology that enables an appropriate scenario to be selected from a plurality of scenarios based on a simulation of a wireless communication system.

[0011] It is a diagram showing an example of the configuration of a wireless communication system to be a target of a simulation. It is a diagram showing the configuration of a selection device 100. It is a diagram showing the configuration of the selection device 100. It is a flowchart for explaining the operation of the selection device 100. It is a diagram showing an example of the hardware configuration of the selection device 100.

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0013] A technique for selecting an appropriate scenario from among multiple scenarios based on a simulation of a wireless communication system will be described in detail below.

[0014] (System Configuration Example) An example of the overall configuration of a wireless communication system according to this embodiment is shown in Fig. 1. This wireless communication system is an example of a wireless communication system that is the subject of simulation and also the subject of actual control.

[0015] 1, the wireless communication system includes a plurality of wireless nodes 10 and a plurality of terminals 20 that communicate wirelessly with the wireless nodes 10. The wireless nodes 10 are, for example, base stations, RISs (Reconfigurable Intelligent Surfaces), etc. The terminals 20 are, for example, general terminals such as smartphones.

[0016] The wireless node 10 is assumed to be movable, but some of the multiple wireless nodes 10 may not be movable. Furthermore, parameters of the wireless node 10, such as the antenna direction, reflector direction, beam direction, and transmission power, can be changed arbitrarily. Information indicating how to change the parameters is included in a scenario, which will be described later. The scenario may also be called a "control amount."

[0017] The wireless communication system in this embodiment is not limited to a specific wireless method, but may be, for example, 5G, wireless LAN, or the like.

[0018] Furthermore, from a simulation perspective, this wireless communication system is treated as a digital twin space that includes obstacles to radio wave propagation, such as buildings. A digital twin space is a space that simulates the real environment of the area covered by the wireless communication system using a 3D model or the like. Mobile objects such as humans and robots may be considered as radio wave obstructions. Furthermore, the digital twin space may be constructed based on sensing information in the real space, and a model corresponding to the digital twin space may be corrected based on this sensing information.

[0019] By simulating the digital twin space of a wireless communication system, it is possible to estimate the received radio wave strength or throughput in a certain area, for example, based on a certain scenario, when a base station as a wireless node is installed in a certain location and the RIS reflector is set at a certain angle.

[0020] In this embodiment, it is assumed that a simulation is performed to evaluate, for example, the communication quality (for example, received signal strength, throughput) of a certain terminal while changing changeable parameters based on a scenario.

[0021] (Device Configuration Example) In this embodiment, the selection device 100 selects one scenario from among a plurality of scenarios based on a simulation, using a procedure described below.

[0022] Fig. 2 shows an example configuration of the selection device 100. As shown in Fig. 2, the selection device 100 has an input unit 110, a scenario creation unit 120, a simulation execution unit 130, a probability distribution calculation unit 140, a selection unit 150, an output unit 160, and a data storage unit 170. The operation of each unit will be explained in the processing procedure section. The simulation execution unit 130 and the probability distribution calculation unit 140 may be collectively referred to as the "calculation unit."

[0023] The configuration shown in FIG. 2 is a configuration assuming that the selection device 100 selects a scenario, and that the actual control of the wireless communication system is performed by another device.

[0024] The selection device 100 may select a scenario and also perform subsequent control. The device configuration in this case is shown in FIG. 3. As shown in FIG. 3, in this configuration example, the selection device 100 has an input unit 110, a scenario creation unit 120, a simulation execution unit 130, a probability distribution calculation unit 140, a selection unit 150, a control unit 180, a correction unit 190, and a data storage unit 170. The operation of each unit will be explained in the processing procedure section. In the following explanation, the operation of the selection device 100 will be explained mainly using the configuration shown in FIG. 3 as an example.

[0025] (Example of Operation of Selection Device 100) An example of operation of the selection device 100 will be described in accordance with the procedure of the flowchart shown in Figure 4. In the following operation, it is assumed that the information necessary to configure the digital twin space of the wireless communication system has been stored in advance in the data storage unit 170.

[0026] <S101 (Step 101)> In S101, for example, a user inputs an instruction to perform a simulation (and control) from the input unit 110. This instruction triggers the execution of the subsequent processing.

[0027] The trigger for the simulation is not limited to a user instruction. For example, the simulation (and control) may be started at a preset time. Alternatively, the input unit 110 may receive a sensing result, an amount of environmental change, or an amount of traffic change in the wireless communication system, and determine whether to perform the simulation based on the value (e.g., whether the value exceeds a threshold).

[0028] When a simulation is triggered based on any of the above events, the process proceeds to S102.

[0029] <S102> In S102, the scenario creation unit 120 places one or more predetermined candidate wireless nodes at candidate installation locations for one or more predetermined wireless nodes (base stations, relay stations, etc.) in the digital twin space, and creates multiple scenarios in which candidate setting parameters are applied to the placed wireless nodes. The multiple scenarios are stored in the data storage unit 170. The scenarios may also be called control amounts.

[0030] Examples of information that make up a scenario are as follows:

[0031] - Location of base station, direction of base station antenna - Role of relay node (regenerative relay, RIS, metamaterial lens, etc.), location of relay node, direction of relay node (direction of antenna or reflector) - Beam set (information on which beam to use), antenna information - Transmission power - Frequency used A scenario may include all of the above information, may include only a part of the above information, or may include information other than the above information.

[0032] Alternatively, the scenario creation unit 120 may not be provided, and multiple scenarios may be stored in advance in the data storage unit 170. Alternatively, multiple scenarios may be input from the input unit 110.

[0033] <S103, S104, S105> In S103, the simulation execution unit 130 executes a simulation for each of the multiple scenarios created in S102.

[0034] In S104, the probability distribution calculation unit 140 calculates the probability distribution of the evaluation index for each scenario for which a simulation has been performed.

[0035] In S105, the selection unit 150 selects from the multiple scenarios the scenario that has the highest probability of maximizing the evaluation index. In this embodiment, the larger the evaluation index, the better.

[0036] The processes of S103 to S105 will be described in more detail below using an example. Note that a simple example is used here to make the explanation easier to understand.

[0037] (1) Regarding the scenarios Here, it is assumed that in S102, the scenario creation unit 120 has determined two scenarios: changing the antenna direction of the base station from direction A to direction B (scenario 1), and changing the antenna direction of the relay node from direction C to direction D (scenario 2) in order to increase the received radio wave strength at a certain location P in a certain real space (digital twin space in the selection device 100) where a base station and a relay node are installed.

[0038] (2) Regarding the simulation In S103, the simulation execution unit 130 executes a simulation (simulation 1) for scenario 1 (setting the base station antenna direction to direction B) using a digital twin space corresponding to the real space, and calculates the received radio wave strength at location P.

[0039] The simulation execution unit 130 also executes a similar simulation (simulation 2) for scenario 2 (setting the antenna direction of the relay node to direction D) and calculates the received radio wave intensity at location P.

[0040] (3) Calculation of probability distribution The probability distribution calculation unit 140 calculates the probability distribution of received radio wave strength at location P in scenario 1 based on the results of simulation 1, and calculates the probability distribution of received radio wave strength at location P in scenario 2 based on the results of simulation 2.

[0041] The method for calculating the probability distribution is not limited to a specific method, but for example, multiple simulations can be performed in a digital twin space (including factors that cause fluctuations in received radio wave strength) to calculate multiple received radio wave strengths, and a probability distribution (which may be a frequency distribution) can be obtained from that data. For example, assuming that the probability distribution is a normal distribution, the probability distribution can be calculated as a normal distribution with the mean and variance of the above data.

[0042] The radio wave intensity may be converted into throughput using a conversion table or the like, and the probability distribution of the throughput may be calculated.

[0043] (4) Probability Distribution of Evaluation Index Here, the evaluation index is defined as "evaluation index = A × received signal strength + B × cost", where A and B are predetermined parameters (coefficients). The probability distribution calculation unit 140 calculates the probability distribution of "A × received signal strength + B × cost" based on the probability distribution of received signal strength and the probability distribution of cost.

[0044] The cost is the cost (expense) required to execute the scenario. The cost may be a definitively determined value. In addition, the types of expenses to be included in the cost may be determined arbitrarily depending on the purpose, etc. For example, the cost may be calculated as a value obtained by adding up the normalized values ​​of the price of the equipment used, the installation cost (time), and the cost (time) related to transportation.

[0045] Furthermore, if throughput is used instead of received radio wave strength, the evaluation index becomes “A×throughput+B×cost.” Both received radio wave strength and throughput are examples of indexes related to communication quality.

[0046] (5) Regarding Scenario Selection The selection unit 150 selects, from among multiple scenarios, the scenario that has the highest probability of maximizing the evaluation index.

[0047] As an example, if the maximum value of the evaluation index (= A x received signal strength + B x cost) in scenario 1 is 10 and the probability is 0.4, and the maximum value of the evaluation index (= A x received signal strength + B x cost) in scenario 2 is 15 and the probability is 0.3, then scenario 2 will be selected because "10 x 0.4 < 15 x 0.3".

[0048] The selection unit 150 may also select a scenario based on the expected value (or a value equivalent thereto) of the evaluation index that takes into account the probability distribution. In this case, the selection unit 140 calculates Σ (evaluation index × probability) as the expected value for each scenario. Σ means the sum of "evaluation index × probability" for the evaluation index. The selection unit 140 selects the scenario with the largest expected value from among multiple scenarios.

[0049] In the above specific example, if the expected value in scenario 1 is calculated as 20 and the expected value in scenario 2 is calculated as 30, scenario 2 is selected.

[0050] When it is assumed that the selection device 100 shown in Fig. 2 is used, the selection device 100 outputs the selected scenario from the output unit 160. When the selection device 100 shown in Fig. 3 is used, the process proceeds to the next step S106.

[0051] <S106> The control unit 180 controls the actual wireless communication system according to the scenario selected in S105. For example, in the above specific example, if scenario 2 (setting the antenna direction of the relay node to direction D) is selected, the control unit 180 executes control to set the antenna direction of the relay node to direction D.

[0052] After the above control, the correction unit 190 may correct the control based on sensing information, etc. For example, when the correction unit 190 determines that better quality can be obtained by correcting the antenna direction of the relay node from direction D to direction E based on information on the received power for each beam at the terminal, the correction unit 190 executes control to correct the antenna direction of the relay node from direction D to direction E.

[0053] (Hardware Configuration Example) The selection device 100 described in this embodiment can be realized, for example, by causing a computer to execute a program. This computer may be a physical computer or a virtual machine on the cloud.

[0054] That is, the selecting device 100 can be realized by using hardware resources such as a CPU and memory built into a computer to execute a program corresponding to the processing performed by the selecting device 100. The program can be recorded on a computer-readable recording medium (such as a portable memory) and can be saved or distributed. The program can also be provided via a network such as the Internet or email.

[0055] Fig. 5 is a diagram showing an example of the hardware configuration of the computer. The computer in Fig. 5 includes a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a CPU 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, and the like, all of which are interconnected via a bus B. The computer may further include a GPU.

[0056] The program that realizes the processing on the computer is provided by a recording medium 1001, such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed from the recording medium 1001 to the auxiliary storage device 1002 via the drive device 1000. However, the program does not necessarily have to be installed from the recording medium 1001, but may be downloaded from another computer via a network. The auxiliary storage device 1002 stores the installed program as well as necessary files, data, etc.

[0057] The memory device 1003 reads and stores the program from the auxiliary storage device 1002 when an instruction to start the program is received. The CPU 1004 realizes functions related to the selection device 100 in accordance with the program stored in the memory device 1003. The interface device 1005 is used as an interface for connecting to a network, etc. The display device 1006 displays a GUI (Graphical User Interface) or the like according to the program. The input device 1007 is composed of a keyboard, mouse, buttons, a touch panel, etc., and is used to input various operation instructions. The output device 1008 outputs the results of calculations.

[0058] (Summary, Effects, etc. of the Embodiment) As described above, the technology according to the embodiment makes it possible to select an appropriate scenario from among a plurality of scenarios based on a simulation of a wireless communication system, taking into consideration the probability distribution of communication quality, etc. This makes it possible to implement control that maximizes the probability of maximizing an evaluation index, for example.

[0059] The following additional notes are provided regarding the above-described embodiments.

[0060] <Additional Notes> (Additional Item 1) A selection device for selecting a specific scenario to be applied to control from a plurality of scenarios to be simulated in a wireless communication system, comprising: a memory; and at least one processor connected to the memory, wherein the processor calculates a probability distribution of an evaluation index by executing a simulation for each of the plurality of scenarios, and selects the specific scenario from the plurality of scenarios based on the probability distribution. (Additional Item 2) The selection device according to Additional Item 1, wherein the evaluation index includes an index related to communication quality and a cost for executing a scenario. (Additional Item 3) The selection device according to Additional Item 1 or 2, wherein the processor selects as the specific scenario a scenario that maximizes the sum of values ​​obtained by multiplying the evaluation index by the probability of the evaluation index. (Additional Item 4) The selection device according to any one of Additional Items 1 to 3, wherein the processor performs control over the wireless communication system based on the specific scenario. (Supplementary Item 5) A selection method executed by a selection device for selecting a specific scenario to be applied to control from a plurality of scenarios to be simulated in a wireless communication system, the selection method comprising: a calculation step of calculating a probability distribution of an evaluation index by executing a simulation for each of the plurality of scenarios; and a selection step of selecting the specific scenario from the plurality of scenarios based on the probability distribution. (Supplementary Item 6) A non-transitory storage medium storing a program for causing a computer to function as each unit in the selection device described in any one of Supplementary Items 1 to 4.

[0061] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0062] 10 Wireless node 20 Terminal 100 Selection device 110 Input unit 120 Scenario creation unit 130 Simulation execution unit 140 Probability distribution calculation unit 150 Selection unit 160 Output unit 170 Data storage unit 180 Control unit 190 Correction unit 1000 Drive device 1001 Recording medium 1002 Auxiliary storage device 1003 Memory device 1004 CPU 1005 Interface device 1006 Display device 1007 Input device 1008 Output device

Claims

1. A selection device for selecting a specific scenario to be applied to control from a plurality of scenarios to be simulated in a wireless communication system, comprising: a calculation unit that calculates a probability distribution of an evaluation index by executing a simulation for each of the plurality of scenarios; and a selection unit that selects the specific scenario from among the plurality of scenarios based on the probability distribution.

2. The selection device according to claim 1, wherein the evaluation index includes an index related to communication quality and a cost for executing the scenario.

3. The selection device according to claim 1, wherein the selection unit selects, as the specific scenario, a scenario in which the sum of the values obtained by multiplying the evaluation index by the probability of the evaluation index is maximized.

4. The selection device according to claim 1, further comprising a control unit that controls the wireless communication system based on the specific scenario.

5. A selection method executed by a selection device for selecting a specific scenario to be applied to control from a plurality of scenarios to be simulated in a wireless communication system, comprising: a calculation step of calculating a probability distribution of an evaluation index by executing a simulation for each of the plurality of scenarios; and a selection step of selecting the specific scenario from among the plurality of scenarios based on the probability distribution.

6. A program for causing a computer to function as each unit in the selection device according to any one of claims 1 to 4.

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